Device for remotely lining a steam generator tube of a pressurized water nuclear reactor

ABSTRACT

A liner (12) is inserted into the water box (3) through the manhole (9) vertically in line with the manhole, and then the liner (12) is moved as far as a position situated vertically in line with the tube (8) to be lined. The operations of inserting the liner (12) into the tube (8), of diametral expansion and of roller-expanding are performed by inserting a corresponding appliance into the water box (3) and using this appliance from an operating station outside the water box, where the drive for the appliance is situated.

This is a Division, of application Ser. No. 044,254, filed Apr. 30,1987, now U.S. Pat. No. 4,793,044.

FIELD OF THE INVENTION

The invention relates to a device for remotely lining a steam generatortube of a pressurized water nuclear reactor.

BACKGROUND OF THE INVENTION

Steam generators of pressurized water nuclear reactors generallycomprise a bundle consisting of a very large number of narrow-bore tubesbent into a U and fastened at each of their ends by crimping into athick tube plate. The part of the steam generator which is situatedbelow the tube plate forms a water box, in a first part of which thepressurized water coming from the reactor vessel is distributed into thebundle tubes, and in a second part of which the water which hascirculated in the tubes is recovered, to be re-directed, via a primarycircuit conduit of the reactor, into the vessel enclosing the core,which consists of fuel assemblies responsible for the heating of thepressurized water. The steam generator feed water comes into contactwith the outer surface of the bundle tubes, in the part of the steamgenerator which is situated above the tube plate.

The walls of the bundle tubes thus constitute a barrier between thepressurized water forming the primary fluid of the reactor and the feedwater forming the secondary fluid. The primary water, which comes intocontact with the fuel assemblies and the internal structures of thereactor vessel, contains radioactive products in more or lesssubstantial quantities. The steam produced in the steam generator, byheating and vaporization of the feed water, is conveyed to a turbineassociated with the nuclear reactor. It is therefore necessary to avoidany contact between the primary fluid and the secondary fluid, whosecontamination could have highly detrimental consequences.

It is thus necessary to avoid as completely as possible the appearanceof leakages through the walls of the bundle tubes of the steam generatorand to repair as quickly as possible and effectively the bundle tubeswhose wall has been perforated.

Because of the stresses of thermal and mechanical origin or thecorrosion to which the bundle tubes are subjected, cracks can form inthe walls of the bundle tubes, both on the primary side and on thesecondary side, while the steam generator is in use.

In order to increase the lifespan of the steam generators and to ensurethat this lifespan is similar or equal to that of the other componentsof the reactor, interventions or repairs must be carried out to thebundle tubes, during the periods of maintenance of the nuclear reactor.

To date one of the most widely used techniques has consisted in takingthe defective tube or tubes out of service by inserting and fastening aplug in a leakproof manner in the end of the tube which is flush withthe tube plate and which the primary water enters. A disadvantage ofthis technique is that it reduces the exchange surface of the steamgenerator, the degree of such reduction increasing with the number oftubes taken out of service.

Processes for repairing the bundle tubes of a steam generator by liningthese tubes have therefore been proposed, where the defect leads to aseal loss. A tubular sleeve or liner, with an external diameter which isslightly smaller than the internal diameter of the tube to be repairedand with sufficient length to overlap the defect, is inserted into thetube, through the entry face of the tube plate with which the ends ofthe tubes are flush. The liner itself is placed in the tube, inside thetube plate, so as to be flush with the entry face of the tube plate. Theliner is then fastened to the interior of the tube by diametralexpansion, followed by one or more operations permitting a leakproofconnection to be made between the sleeve and the tube on each side ofthe defective region of the tube.

In particular, it is known to perform a diametral expansion of the linerin two regions in the vicinity of its ends, situated, in the case ofone, within the thickness of the tube plate in the vicinity of its entryface and, in the case of the other, beyond the exit face of the tubeplate, so that these two regions are situated on either side of thedefective region of the tube to be repaired. The leakproof joint betweenthe liner and the tube is produced by a roller-expanding operation onthe liner in each of the regions which have been subjected to thediametral exapanion.

All these operations require an intervention inside the water box of thesteam generator, i.e., in a part of this generator which comes intocontact with the primary water carrying radioactive products, while thereactor is in operation.

When these operations are performed manually, an operator has to enterthe water box, where he is exposed to high radioactivity. The time forwhich the operator is present in the water box must therefore be reducedto the minimum, with the result that it is possible to perform only asmall proportion of the tasks required for lining a tube, when this isdone by an operator. This operator then becomes unavailable forcontinuing the operations of lining the tubes inside the water box,since his radiation dose reaches the upper limit which is gnerallypermitted. In order to perform the operations on a steam generator,especially in the case where several tubes need to be lined, a largenumber of competent and trained operators must therefore be available,and this considerably increases the manpower costs during themaintenance operations on the nuclear reactor.

Automatic appliances have therefore been proposed for performing atleast partially the operations which are necessary for lining the tubesof a steam generator. Such appliances, which must perform the placing ofthe liner in a specified tube of the steam generator, then itsexpansion, its roller-expanding and/or its welding in a completelyautomatic manner, are extremely complicated and extremely bulky, sincethey need to comprise all the means necessary for the various successivestages of the lining operation and, in particular, all the means fordriving the various tools used in succession. Furthermore, the capacityof such an appliance, insofar as the number of tubes which can be linedone after another without withdrawing the appliance from the water boxis concerned, is, after all, limited by the maximum number of linerswith which the appliance can be equipped at the time when it is insertedinto the water box. Devices which have a barrel magazine containingseveral liners which can be presented in succession have been designed,to enable the latter to be inserted into the tubes to be lines. However,the capacity of such barrel magazines must be limited if excessive bulkand complexity of the appliance are to be avoided.

SUMMARY OF THE INVENTION

The purpose of the invention is therefore to propose a device forremotely lining a steam generator tube of a pressurized water nuclearreactor, the tube having two ends crimped into a tube plate below whichthe steam generator forms a water box accessible from outside via amanhole. The process comprises, in a known manner, the insertion of aliner into the tube through one of its ends, the diametral expansion ofthe liner in at least two regions situated in the vicinity of its ends,one of these regions being within the thickness of the tube plate andthe other beyond this tube plate and, lastly the roller-expanding of thetube in each of the expansion regions, this process making it possibleto perform the lining in a completely automatic manner from an operatingstation situated outside the water box, with a simple appliance of lowbulk, having an unlimited intervention capacity.

To this end, in an automatic manner, with remote control from anoperating station situated outside the water box, a liner is insertedinto the water box, through the manhole, as far as a location situatedunder the tube plate vertically in line with the manhole, the liner ismoved inside the water box as far as a position situated under the tubeplate vertically in line with one of the ends of the tube to be lined,and the operations of insertion of the liner into the tube, of diametralexpansion and of roller-expanding, in the region situated outside thetube plate, are performed by inserting a corresponding appliance intothe water box and using this appliance by controlling driving meanssituated at the opeating station outside the water box.

The invention also relates to a device for carrying out the liningprocess according to the invention from an operating station situatedoutside the water box.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more clearly understood, adescription will now be given, by way of example, of a device forremotely lining steam generator tubes of a pressurized water nuclearrector and for using it in a lining process according to the invention.

FIG. 1 is a perspective view, with cutaway, of the water box of a steamgenerator.

FIG. 2 is an enlarged view in partial section of a part of a steamgenerator and of two lined tubes of this steam generator.

FIG. 3a is an enlarged sectional view of a steam generator tube, in anintermediate stage of a lining operation.

FIG. 3b is an enlarged sectional view of a steam generator tube, at theend of a lining operation.

FIG. 4 is a general diagrammatic view of the appliance used during theinsertion of a lining liner into the water box of a steam generator.

FIG. 5 is a view along V of FIG. 4.

FIG. 6 is a general diagrammatic view of the appliance used during thestages of insertion and of expansion of a lining liner in a steamgenerator tube.

FIG. 7 is a sectional view of a device for guiding and for insertion ofthe appliance into a steam generator tube in which a lining operation isperformed.

FIG. 8 is a sectional view through a vertical plane of a loading boxforming part of the appliance* shown in FIGS. 4 and 6.

FIG. 9 is a view along IX--IX of FIG. 8.

FIG. 10 is a sectional view of a device for the diametral expansion of alining liner.

FIG. 11 is a general diagrammatic view of the appliance used for theroller-expanding of a lining liner in the region situated outside thetube plate, when it is inserted into the water box of a steam generator.

FIG. 12 is a general diagrammatic view of the roller-expanding applianceshown in FIG. 11, when it is inserted into a steam generator tube duringthe lining operation.

FIG. 13 is a detailed perspective view of the drive assembly of theroller-expanding device shown in FIGS. 11 and 12.

FIG. 14 is a diagrammatic sectional view of the roller-expanding toolassembly.

FIG. 15 is a detailed sectional view of the end part of theroller-expanding tool shown in FIG. 14.

DESCRIPTION OF PREFERRED EMBODIMENT

FIG. 1 shows a steam generator 1 comprising a thick tube plate 2 underwhich the lower part of the steam generator forming a water box 3 isfastened. The water box 3, of hemispherical shape, is divided into twoparts by a partition 5. The high-temperature pressurized water from thenuclear reactor enters one of the parts of the water box through a pipe6 and then circulates in the bundle tubes 8 of the steam generator,first upwards and then downwards, to come out into the second part ofthe water box, into which opens a pipe 7 connected to the primarycircuit of the nuclear reactor, for returning the pressurized water tothe reactor vessel.

Each of the parts of the water box 3 is provided with a manhole 9 whichcan be closed by a closure cover 10.

FIG. 2 shows a part of the tube plate 2 of the steam generator, throughwhich the ends of two tubes 8a and 8b pass and are crimped byroller-expanding within holes which pass through the tube plate. Thetubes 8a and 8b either project very slightly from, or are flush with,the lower face 2a, or entry face, of the tube plate 2. The tubes 8a and8b pass through the exit face 2b of the tube plate to enter the upperpart of the steam generator receiving the feed water, which is heatedand vaporized by the pressurized water circulating in the tubes 8. Thetube region in the vicinity of the exit face 2b of the tube plate, whichcorresponds to the transition zone between the part distorted byroller-expanding and the undistorted part of the tubes, is generally thepart of the tube which is the most liable to cracking, especially due tothe action of corrosion. In order to repair the tubes cracked in theregion 11 in the vicinity of the exit face 2b of the tube plate, alining operation may be performed by inserting and fastening into thecracked tube a liner 12 overlapping the region 11 in which the tube iscracked.

FIG. 2 shows two types of liner 12a and 12b which enable the repair oftubes 8a and 8b, respectively to be carried out. Liner 12a, whose lengthis greater than the thickness of the tube plate 2, may be inserted, fromthe entry face 2a of the tube plate, into any tube which it is necessaryto repair, so that the lower end of the liner is situated in the regionof the entry end of the tube 8. The upper part of the liner thenoverlaps the region 11 in which the tube 8a is cracked.

However, in the case of peripheral tubes such as tube 8b, it has provedimpossible to insert into this tube a liner of a length greater than thethickness of the tube plate, because of the hemispherical shape of thewater box 3. It is then possible to use a short liner 12b, whose lengthis appreciably smaller than the thickness of the tube plate. This liner12b is placed inside the tube 8b so as to overlap the cracked region 11.Its lower end is then within the tube plate and not at the level of theentry face 2a of this tube plate.

This new process for lining the peripheral tubes of a steam generator isthe subject of a patent appliaction by the assignee of the presentapplicants filed on the same date as the present application.

FIGS. 3a and 3b show a peripheral tube 8b in the process of being linedand after the lining operation, respectively, using a short liner 12b.

In FIG. 3a, the liner 12b inserted into the tube 8b has undergone adiametral expansion in its smaller part situated in the part of the tube8b which is roller-expanded inside the tube plate 2. This intermediatestage of the lining is followed by a stage during which the diametralexpansion of the liner 12 is produced in a region 13 situated above thetransition zone 11 in which a crack 14 has been detected. This diametralexpansion is performed in a region which is beyond the exit face 2b ofthe tube plate, i.e., outside the region of the tube 8 which is crimpedinto the tube plate 2.

The liner 12b is then roller-expanded inside the tube 8 in its end zone15; situated within the crimped part of the tube 8.

Lastly, the liner 12 is also roller-expanded inside the tube 8 in aregion 16 situated within the diametral expansion region 13.

The roller-expanding operations which are performed in the regions 15and 16 inside the regions of the liner 12 which have previously beensubjected to a radial expansion make it possible to ensure a leakproofjoint between the liner 12 and the tube 8 on either side of the region11 comprising a crack 14. The tube 8 can then once again ensure theseparation between the primary fluid and the secondary fluid, after thesteam generator has been started up.

The sealing of the roller-expanded regions 15 and 16 may be improved bybrazing or welding.

The operations just described are known in the prior art and, to beimplemented, require the intervention by an operator in the water box ofthe steam generator, or the use of a semi-automatic device, which iscomplicated, bulky and limited in capacity.

The object of the invention is to propose a process and a deviceenabling these disadvantages to be overcome.

FIGS. 4, 5 and 6 show the set of means required for performing theinsertion of a liner into the water box 3, from an operating station 18situated outside this water box, followed by the installation of theliner in a tube to be repaired and, lastly, the diametral expansion ofthe liner in two regions in the vicinity of its ends, as shown in FIGS.3a and 3b.

In FIG. 4, the components of the device are in their position whichpermits the liner to be inserted into the water box.

In FIG. 6, the corresponding components are in their position enablingthe liner to be inserted into the tube to be repaired and to be expandedhydraulically.

The steam generator tube lining operations are carried out on the steamgenerator which has been stopped, emptied of water and cooled, at leastone of the manholes 9 being open to allow the insertion of appliancesinto the water box.

Before the lining operations as such, a manipulating device 19 isinserted and mounted in the water box 3, this device being well known inthe prior art and comprising an arm 20 made up of two articulatedsections allowing an appliance to be positioned under the tube plate 2,precisely vertically in line with the end of any tube of the bundle.

In order to implement the invention, a guiding and insertion device 21,of overall tubular shape, which will be described in more detail withreference to FIG. 7, is attached to the end of the arm 20, in a verticalposition.

In FIG. 4, the position of the arm 20 of the manipulating device 19 issuch that the tubular guiding member 21 is vertically in line with amanhole 10 of the water box 3. In this position, a lining liner can beinserted into the water box.

The components of the device which are situated at the operating station18 outside the water box comprise a winding and unwinding device 22, apuller-pusher 23 and a loading tube 24. A rotating coupling 25 connectedto a high pressure fluid source 26 is coupled to the winding andunwinding device 22, to supply high pressure fluid to a flexible tubewhich is manipulated by the winding and unwinding device 22.

As can be seen in FIGS. 4 and 5, the puller-pusher 23 has rollers 28which are integrally fastened to gears 29 driven by a driving devicewhich is (not shown). A flexible tubular member 30 stored in the windingand unwinding device 22 and connected to the pressure source 26 via thecoupling 25 passes between the driving rollers 28 of the puller-pusher,which can make it travel in either direction. The loading tube 24 isattached at one of its ends to the outlet of the puller-pusher and, atits other end, is connected to a flexible tube 31 which provides theconnection between the outlet of the loading tube 24 and the tubularguiding and insertion member 21 inside the water box. This flexible tube31, about 5 meters in length, enables the operating station 18 to beplaced completely outside the region which is exposed to the radiationfrom the water box 3. This tube 31 will preferably consist of astainless steel tube having successive undulations over its entirelength and surrounded by a protective plaited sheath made of stainlesssteel wires.

FIG. 7 shows the tubular guiding member 21 connected to the end of thearm 20 by means of a liner 33 in which the tubular member 21 is mountedso that it can slide. A double-action jack 36 whose body is attached tothe liner 33 and whose rod is coupled to the tubular member 21 enablesthis member 21 to be moved in either direction or to be held inposition.

At its upper end 21a, the tubular member 21 has an internal diameterwhich is smaller than in its running part and forms a re-entrant profilewhich enables it to exert a pull on the hydraulic expander 34 connectedto the end of the flexible tubular member 30 when the latter is inengagement with the liner 12 in a tube 8 which is being repaired. Thedouble-action jack 36 thus makes it possible to exert a pull on theexpander, at the end of the stage of hydraulic expansion of the liner,as will be explained later. The double-action jack 36 also makes itpossible, after the arm 20 has been positioned vertically in line with atube 8, to position the upper end of the tubular guiding member 21 sothat it is in the immediate proximity of the projecting end of the tube8 or is even in engagement with the latter, when the tube 8 extendsbeyond the tube plate, since the upper end of the tubular member 21 isfunnel-shaped.

The lower end of the tubular member 21 is connected via a rotary ballcoupling 35 to the flexible tube 31, so that the tube 31 can rotaterelative to the tubular guiding member 21.

FIG. 8 shows that the loading tube 24 is mounted on a supportingstructure 37 comprising a longitudinal girder 38 consisting of aT-section beam, two flanges 39 and 40 fastened to the ends of thelongitudinal girder 38, and an adjustable supporting tripod 41. The tube24 itself consists of two half-covers 24a and 24b mounted articulatedaround pivots 27 and 27', on the support 37. In FIG. 9, the twohalf-covers 24a and 24b are shown in full lines in their closed positionand in broken lines in their open position. In their closed position,the two half-covers form a continuous and closed tube, connected at itsends to couplings 42 and 43 which are integrally fastened to the flanges39 and 40, respectively. The coupling 42 enables the end of the flexibletube 31 to be connected to the outlet of the loading tube 24, by virtueof a fast-acting snap coupling 44 fitted with a locking means and a ballassembly allowing the flexible tube 31 to rotate relative to the loadingtube 24. Thus, at one of its ends, the flexible tube is fastened to thetubular guiding member 21 inside the water box 3 and, at its other end,to the loading tube 24, outside the water box. Furthermore, both ends ofthe tube are so mounted that they can rotate freely on the components towhich they are coupled.

The coupling 43 provides the connection between the loading tube 24 andthe puller-pusher 23, so that the flexible tubular member 30 coming fromthe winding and unwinding device 22 can pass from the puller-pusher tothe loading tube without any interruption of guidance.

Two fast-locking devices 45 allow the two half-covers 24a and 24b to belocked in a closed position. A safety interlock prevents the operationof the puller-pusher when the half-covers 24a and 24b are in an openposition.

A force-sensor (not shown), is placed between the loading tube 24 andthe quick coupling 44 to ensure that the puller-pusher stopsautomatically, should the measured force exceed some predeterminedvalue.

FIG. 10 shows a liner 12 which can be used for lining a steam generatortube, into which has been inserted a hydraulic expander 34, one of whoseends is connected, by virtue of a fixed coupling 50, to a length offlexible tube similar to the tube 30 stored in the winding device 22 andmoved by the puller-pusher 23, this length of flexible tubing beingitself connected to the end of the flexible tube 30 by means of aremovable coupling 51, consisting of two parts. For this purpose, one ofthe parts of the removable quick coupling 51 is fastened to the end ofthe flexible tube 30 and the other part to the end of the intermediatelength fastened to the expander.

The coupling 50 has a shoulder on which the liner 12 abuts when it isinserted into the expander mandrel. The coupling 50 has a shoulder whichcomes to bear on the lower face of the tube place (in the case of theshort liners) and which thus positions the liner at the required heightin the tube 8.

Arranged inside the tube 30 is a capillary tube 52, one end of which isfastened in the part of the quick coupling 51 which is integrallyattached to the tube 30, and the other end of which is connected to therotary coupling 25 of the winding device 22. An identical capillary tube52' is fastened in the flexible length connected between the expander 54and the coupling 51. One of the ends of this capillary tube 52' isconnected to the expander 34 by means of the fixed coupling 50, and theother end of this capillary 52' is connected to the part of theremovable quick coupling 51 connected to the flexible connecting length.The snap fastening of the quick coupling 51 enables the capillaries 52and 52' to be joined together. In this manner, using this capillarytubing, the supply of the expander 34 with pressurized hydraulic fluidfrom the source of pressurized hydraulic fluid 26 can be ensured.

The capillary tubes 52 and 52' comprise helically wound parts 53 whichenable the capillary to have a degree of flexibility when the flexibletube 30, the liner 12 and the expander 34 travel inside the flexibletube 31.

The expander 34 has a lower expansion chamber 55, an upper expansionchamber 56 and a central body 54 perforated with an axial channelenabling the expansion chambers 55 and 56 to be interconnected. Thelower expansion chamber 55 communicates with the end of the capillary52' in order to be supplied iwth pressurized fluid. The upper expansionchamber 56 is supplied with pressurized fluid from the chamber 55, viathe channel in the central body 54 of the expander.

The entry of pressurized fluid into the expansion chambers 55 and 56enables their jackets to dilate in the radial direction and to transmitthis radial deformation to the liner 12, when this liner has beeninserted into the tube 8 which is to be lined.

Reference will now be made to FIGS. 4 and 6 in order to describe theoperation of the device during the stages of insertion and of expansionof a lining liner in a steam generator tube.

To start with, the arm 20 and the guiding and insertion device 21 are inthe position shown in FIG. 4. An operator placed at the operatingstation 18 opens the loading tube 24 by separating the two half-covers24a and 24b after ensuring the unlocking of the devices 45.

A lining liner 12, into which an expander 34, connected to a length offlexible connection, has been inserted, as shown in FIG. 10, is theninserted into the open loading tube. The flexible connecting length isconnected to the end of the flexible tube 30 by means of the removablequick coupling 51.

The loading tube 24 is then closed and locked, and then thepuller-pusher 23 is started up, in the pushing direction, to move theflexible tube 30 carrying, at its end, the liner 12 and the hydraulicexpander 34, first into the loading tube 12 and then into the flexibletube 31, until the liner 12 enters the tubular guiding and insertionmember 21.

The length of the flexible tube which is moved by the pusher-puller ismonitored by counting the number of rotations of a mesuring roller incontact with the flexible tube in the puller-pusher 23, and by means ofpresence-detectors placed in the member 21.

The tubular guiding and insertion member 21 is then brought into theposition shown in FIG. 6, vertically in line with the tube 8 which is tobe lined. During the travel of the tubular member 21 from its positionshown in FIG. 4 as far as its position shown in FIG. 6, the flexibletube 31, the tubular flexible member 30 and the capillary tube 52, 52'deformed to follow the motion of the guiding member 21.

When the guiding membr 21 is in a position vertically in line with thetube 8, the double-action jack 36 for vertically moving the tubularguiding member 21 is powered in the direction of the rise of the member21, until the latter docks with the end of the tube 8. The puller-pusher23 is then restarted until the liner 12 has reached its final positioninside the tube 8. This position can be monitored by measuring thedisplacement of the flexible member 30 at the puller-pusher, by means ofdetectors placed in the member 21, by measuring the thrust force on aforce-detector placed between the tube 24 and the coupling 44, and by acamera which monitors the insertion and is situated on the appliance 21.

Pressurized hydraulic fluid is then injected into the capillary tube52-52', from the source 26, in order to feed the hydraulic expander 34.The expansion chambers 55 and 56 dilate and produce a diametralexpansion of the liner 12 inside the tube 8, until the outer wall of theliner 12 comes into contact with the inner surface of the tube 8. Thepressure in the capillary tube and in the xapander is then relaeased andthe expander is extracted by powering the double-action jack 36 of thetubular guiding member 21 in the direction of descent. In fact, it maybe necessary to exert some degree of pull on the expander in order toextract it from the liner 12 and the tube 8, since the walls of theexpansion chambers 55 and 56 retain some residual deformation after thepressure of the hydraulic fluid has been released.

The puller-pusher is then started up in the pulling direction and theexpander is reinserted into the member 21. The member 21 is then broughtvertically in line with the manhole 10. The expander can then berecovered from the end of the flexible tube 30, in the loading tube 24,after this tube has been opened.

The flexible tubular member 30 is generally a plastic tube, andpreferably a Rilsan tube, which has both flexibility and strengthproperties sufficient to ensure the travel in the flexible tube 31 andthe thrust on the lining and the expander.

FIGS. 11 and 12 show the assembly of the device required forimplementing the succeeding stage of the lining process, namely, theroller-expanding of the upper part of the liner, in the region of thetube 8 which is situated outside the tube plate 2.

In FIG. 11, the equipment has been shown in the stage of insertion ofthe roller-expanding appliance into the water box, and in FIG. 12, theequipment has been shown during the stage of insertion of theroller-expanding appliance into the tube during the lining operation.

The components of the equipment which are arranged in the water box areidentical to those used in the preceding stages and shown in FIGS. 4 and6. Similarly, the flexible tube 31, connected to the tubular guidingmember 21 is also used and its end is outside the water box, in thevicinity of the operating station 18. This end is now completely free inthe initial stage shown in FIG. 11, for the manual insertion of theroller-expanding tool 60 into this end of the flexible tube 31. Theroller-expanding tool 60 is connected to a flexible tubular member 61similar to the tubular member 30 and also capable of consisting of aRilsan tube. The tubular member 61 is connected to the movable membersof an insertion device 62, in which the roller-expanding machine is alsoplaced, and which will be described in more detail with reference toFIG. 13.

The insertion device comprises a parallelepipedal casing 63 resting onthe floor at the operating station by means of a pedestal 64. Guide bars65 are fixed inside the casing 63, along its longitudinal direction, andguide plates of rectangular shape 66 are mounted so that they can slideon the bars 65 and inside the casing 63, in the longitudinal directionof the casing. The flexible tubular member 61 passes through each of theplates 66 in its middle zone, so as to be mounted slidingly in theseplates. The end plate 66a carries the roller-expanding machine 67, onwhich the end of the flexible tube 61 is mounted in a rigid manner. Theplates 66 are connected together at each of their top ends and at theend of the casing which is away from the roller-expanding machine, by aset of small chains 68.

A belt 69 having an internal set of cogs is mounted in the casing 63, ontwo, driving and return, pinions 70 and 71, respectively. The drivingpinion 70 is connected to a driving motor (not shown).

The end plate 66a is connected to the belt 69 by means of a coupling bar73.

It will thus be understood that the roller-expanding machine 67 and theflexible tube 61 are driven with a lengthwise motion when the motordriving the belt 69 is switched on. The lengthwise motion may beproduced by a screw-and-nut system instead and in place of the belt.

When the motion is produced in the forward direction, i.e., from rightto left in FIG. 13, the plate 66a drives the roller-expanding machine 67and the tube 61 until the plate 66a comes into contact with the secondplate 66b, which it starts driving; gradually, the flexible tube 61 isthus driven while being guided and kept rigid by the plates 66.

When the motion is produced in the extraction direction, i.e., from theleft to the right in FIG. 13, the plates 66 regain their position shownin the figure, by virtue of the small chains 68.

As can be seen in FIGS. 13, 14 and 15, the roller-expanding machinecomprises a double-action jack 74 comprising a reciprocating piston 75connected via a flexible member 76 to the needle 77 of theroller-expander shown in FIG. 15. The roller-expanding machine 67 alsosomprises a motor enabling the flexible member 76 and the needle 77 tobe rotated to transmit the rotary motion to the rollers 78 of theroller-expander 79. The roller-expander 79 itself is fixed, in its lowerpart, to the flexible tube 61 through which the flexible member 76passes. As shown in FIG. 15, in its working position, theroller-expander abuts with its lower part on the lower end of the liner12 which has previously been subjected to a diametral expansion, asdescribed above.

The needle 77 inserted into the central part of the roller-expander 79is frusto-conical in shape and comes to bear on the rollers 78, both todrive then in rotation and also to push them apart, in order to performthe roller-expanding. For this purpose, the needle 77 may be driven inrotation by the flexible member 76 and simulataneously pushed upwards byvirtue of the action of the jack 74.

A description will now be given, with reference to FIGS. 11 and 12, ofan operation of roller-expanding of the upper part of a liner 12 placedinside a tube 8 and having previously been subjected to a radialexpansion in its two end regions, as described above.

The roller-expanding operation is performed in the upper expansionregion of the liner 12, i.e., to in the region of the tube 8 which isabove the tube plate 2.

To start with, as shown in FIG. 11, the arm 20 of the manipulatingdevice 19 is in a position where the tubular guiding member 21 isvertically in line with the manhole 9 of the water box 3. The flexibletube 31 has its end outside the water box, at the operating station 18.

The operator then inserts the roller-expanding tool assembly 60comprising the roller-expander body 79, the rollers 78 and the needle77, into the flexible tube 31. The insertion of the appliance 60 as faras the guiding member 21 is by hand and its accomplishment is monitoredby the length of flexible tube 61 inserted into the flexible tube 31.

When the insertion of the roller-expanding tool 60 into the tubularguiding member 21 has been accomplished, the end of the flexible tube 31away from the guiding member 21 is connected to the end of the casing 63of the insertion machine 62. The tubular guiding member 21 is thenplaced vertically in line with the tube 8 containing the liner 12 to besubjected to roller-expanding, by rotating the arm 20. The new positionof the arm 20, of the flexible member 31 and of the guiding member 21 isshown in FIG. 12.

The insertion of the roller-expanding tool 60 into the liner 12 is thenaccomplished by virtue of the insertion machine 62, as explained above.

The position of the roller-expanding tool in the liner 12 is monitoredvery accurately and the roller-expanding machine 67 is started up, therotation of the needle 77 and the thrust transmitted by this needlemaking it possible to achieve laminating and crimping of the liner 12,inside the tube 8, in the upper region which has previusly beensubjected to diametral expansion.

When the roller-expanding operation on the upper part of the liner hasbeen accomplished, the assembly of the device permitting theroller-expanding is taken out of the water box and the roller-expandingof the lower part of this liner is performed, this part having beenpreviusly subjected to a diametral expansion by a method known in theprior art, i.e., with an automatic machine carried by the arm 20 of themanipulating device 19.

In fact, the roller-expanding of the upper part of the liner inside thetube 8 involves only relatively low stresses, the wall of the tube 8undergoing a deformation, as shown in FIG. 3b. On the other hand, thelower region of the liner is situated in a part of the tube within thetube plate 2, with the result that the stresses which need to be appliedto accomplish the crimping of the liner 12 by laminating its wall to thewall of the tube are much greater; it is therefore no longer possible totransmit the rotation and the thrust to the needle of theroller-expander by means of a long flexible member as in the case of theroller-expanding of the upper part of the liner.

It is quite obvious that the operations of insertion of a lining linerand of hydraulic expansion of this liner in a tube to be lined will becarried out successively for the group of steam generator tubes whichneed to be lined. This avoids having to dismantle the appliance which isused until all the steam generator tubes which are to be lined have beenfitted with a liner, fastened provisionally by diametral expansion. Inthe same way, the operations of roller-expanding of the upper parts ofthe liners will be performed one after another, for all the tubes to belined. These sequential operations on the steam generator tubes will besupplmented by an operation of roller-expanding of the lower part of theliners, by means of a known prior art technique.

It can be seen that the invention makes it possible to limit orcompletely do away with the presence of an operator inside the water boxof the steam generator to perform the lining of the defective tubes ofthis steam generator, while avoiding the use of a complicated and bulkyall-purpose appliance inserted into the water box of the steamgenerator.

The invention makes it possible to limit the part of the device which isinserted into the water box to what is really necessary foraccomplishing the operations in situ inside the tube to be lined. Thedrive and control components are all arranged outside the water box, andthis makes it very easily possible to have access to these componentsfor monitoring the lining operations or to repair them. The process andthe device according to the invention also make it possible to limit thesize of the part of the appliance which is liable to be irradiatedinside the water box of the steam generator. This appliance can beparticularly simple and its insertion, as well as the insertion of theliner into the water box, are carried out in a very simple and verysecure manner by virtue of a guidance by a continuous flexible tube.

The operations which require the presence of an operator in the waterbox or the use of a complicated and bulky device are limited to theroller-expanding of the lower part of the liner.

The invention is not limited to the embodiments which have beendescribed.

It is possible to use appliances other than those which have beendescribed to carry out the diametral expansion of the liner and theroller-expanding of its upper part.

The guidance of the liner and of the appliances, and the transmission ofmotions to the liner and of the appliances inside the water box, may beprovided by flexible or supple tubes of a structure which is other thanthat described.

Lastly, the invention applies to the lining of any pressurized watersteam generator tube, whatever its location in the water box of thesteam generator and whatever the thickness of the tube plate in whichthe tube to be lined is fastened.

What is claimed is:
 1. Device for remotely lining a steam generator tubeof a pressurized water nuclear reactor, the tube (8) having two endscrimped into a tube plate (2) having a thickness, brelow said tube platesaid steam generator forming a water box (3) accessible from outsidethrough a manhold (9), by insertion of a liner (12) into said tube (8)through one of its ends, diametral expansion of said liner (12) in atleast two expansion regions situated in the vicinity of its ends, one ofsaid regions being within the thickness of said tube plate (2) and theother beyond said tube plate (2), and crimping by roller-expanding ofsaid liner (12) in each of said regions, said device comprising(a) amanipulating means (19) equipped with an arm (20) whose end isvertically alignable with any one of the tubes (8) of said steamgenerator, under said tube plate (2); (b) a tubular guiding member (21)attached to the end of said arm (20) in a direction at right-angles tosaid tube plate (2); (c) a flexible tube (31) attached at one of itsends to said tubular guiding member (21) passing through said manholeand having its other end outside said water box; (d) a loading andmanipulating assembly (22, 23, 24) adapted to be connected to an end ofthe flexible tube (31) which is external to said water box forintroducing and moving a liner (12), inside said flexible tube (31); (e)a hydraulic expander (34) which is placed inside said liner (12) andattached, in order to be moved, to the end of a flexible tubular member(30) which is connected to means for supplying a pressurized hydraulicfluid to said expander (34); and (f) a manipulating and roller-expandingassembly (60, 61, 62) comprising a roller-expanding appliance (60), atubular flexible member (61) and a manipulating device (62), saidroller-expanding appliance being connected to an end of said flexibletubular member, and said manipulating device being arranged outside saidwater box and associated to said flexible member so that said flexiblemember (61) and said roller-expanding appliance (60) can move in saidflexible tubing (31), said roller-expanding appliance (60) being furtherconnected to driving means (67, 74, 75) by flexible member (76) passingthrough said flexible tubular member (61).
 2. Lining device according toclaim 1, wherein the assembly for loading and manipulating the linercomprises a winding and unwinding device (22), a puller-pusher withfrollers (23) and a loading tube (24) connected at one of its ends to theend of the tube (31) situated outside the water box and at its other endto the outlet of the puller-pusher (23), the winding and unwindingdwevice (22) containing a flexible tube (30) passing through thepuller-pusher (23) on leaving the winding device (22).
 3. Lining deviceaccording to claim 2, wherein the flexible tube (30) contains acapillary tube (52) for supplying hydraulic fluid to the expander (34),an end of the capillary tube (52) remote from the end connected to theexpander (34) being connected to a source of pressurized fluid (26) bymeans of a rotary coupling (25) placed on the winding device (22). 4.Lining device according to claim 2, wherein the loading tube (24)comprises two semi-cylindrical half-covers (24f and 24b) articulated ona support (38) for changing from an open position to a closed positionand vice versa.
 5. Lining device according to claim 1, wherein thetubular gudiding member (21) is mounted for sliding movement in adirection at right-angles to the tube plate (2) in a bearing (33)carried by the end of the arm (20) and movable either way in saiddirection by means of a double-action jack (36).
 6. Lining deviceaccording to claim 5, wherein the tubular guiding member (21) comprisesa profiled component (21a) projecting inwards, for withdrawal by pullingof the mandrel (34) inserted into the liner (12).
 7. Lining deviceaccording to claim 1, wherein the manipulating device (62) comprises aset of movable plates (66) guided in a casing (63) along a directionperpendicular to the set of plates (66) and connected to each other bysmall chains (68) and an assembly (69,70,71) for moving an end plate(66a) to which is fastened the end of the flexible tube (61) whichpasses through the other plates in a direction at right angles to theseplates in which it is slideably mounted as to be capable of sliding. 8.Lining device according to claim 1, wherein the roller-expandingappliance comprises a body (79) having rotatable rollers (78) and aconical needle (77) mounted therein, said appliance being connectedthrough its body (79) to the end of the flexible tube (61) remote fromthe manipulating dwevice (62) and, through its needle (77), to the endof a flexible member (76) passing inside the tube (61) and connected atits end remote from the needle (77) to the piston (75) of a jack (74)and to means (67) allowing the flexible member (76) and the needle (77)to be driven in rotation.